Balablok (1973)

The square people all get along nicely and politely with each other until one day they discover a round person. "It's ball-shaped" think they, and so they rather rudely use it as one. Then more round folk turn up and turn the tables. Next thing it's escalated to an army of squares forming the animated equivalent of a Roman turtle against a load of cannonball shaped round ones. Around and round it goes until there is…